Yes, wind and wave power are renewable; New Scientist pulls a Charlie Sheen

In the annals of absurdly sexed up science stories crying for attention like, oh, some addled TV star, we have a new contender. The once-excellent New Scientist, which has started running seriously flawed climate stories, as we’ve seen, now runs this stunner:

Build enough wind farms to replace fossil fuels and we could do as much damage to the climate as greenhouse global warming

Rubbish. Indeed, what is surprising about this entire piece is just how much misinformation it contains. You can read the original, unsexy, somewhat opaque (and probably wrong) paper submitted to Philosophical Transactions of the Royal Societyhere.

Even if it were true that increasing global wind power capacity 300-fold (!) would do as much damage to the climate as greenhouse warming — and there’s no evidence in this study that it would — wind and wave power would still be renewable. As NASA’s Gavin Schmidt wrote me (see below), “The NS headline is wrong.”

I’ve been bombarded with people asking me to respond to this in detail, so here goes.

New Scientist explains the work of Axel Kleidon of the Max Planck Institute for Biogeochemistry this way:

He concludes that it is a mistake to assume that energy sources like wind and waves are truly renewable. Build enough wind farms to replace fossil fuels, he says, and we could seriously deplete the energy available in the atmosphere, with consequences as dire as severe climate change.

UPDATE: Stanford’s Mark Jacobson has emailed me a comment on the paper, which I reprint at the end.

That study finds a maximum extractable amount of wind in the range of 18-68 TW and states “we show with the general circulation model simulations that some climatic effects at maximum wind power extraction are similar in magnitude to those associated with a doubling of atmospheric CO2.”

So Kleidon wrote “some” effects at 68TW might be “similar in magnitude” to 550 ppm — whereas NS says it would have “consequences as dire as severe climate change.” No, I don’t think wind turbines will cause a mass marine extinction or endless sea level rise.

Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, says that efforts to satisfy a large proportion of our energy needs from the wind and waves will sap a significant proportion of the usable energy available from the sun. In effect, he says, we will be depleting green energy sources. His logic rests on the laws of thermodynamics, which point inescapably to the fact that only a fraction of the solar energy reaching Earth can be exploited to generate energy we can use.

When energy from the sun reaches our atmosphere, some of it drives the winds and ocean currents, and evaporates water from the ground, raising it high into the air. Much of the rest is dissipated as heat, which we cannot harness.

At present, humans use only about 1 part in 10,000 of the total energy that comes to Earth from the sun. But this ratio is misleading, Kleidon says. Instead, we should be looking at how much useful energy – called “free” energy in the parlance of thermodynamics – is available from the global system, and our impact on that.

Humans currently use energy at the rate of 47 terawatts (TW) or trillions of watts, mostly by burning fossil fuels and harvesting farmed plants, Kleidon calculates in a paper to be published in Philosophical Transactions of the Royal Society. This corresponds to roughly 5 to 10 per cent of the free energy generated by the global system.

Of the 47 TW of energy that we use, about 17 TW comes from burning fossil fuels. So to replace this, we would need to build enough sustainable energy installations to generate at least 17 TW. And because no technology can ever be perfectly efficient, some of the free energy harnessed by wind and wave generators will be lost as heat. So by setting up wind and wave farms, we convert part of the sun’s useful energy into unusable heat.

For the record, we are currently at some 0.2 TW of wind up from 0.1 TW about three years ago.

“Large-scale exploitation of wind energy will inevitably leave an imprint in the atmosphere,” says Kleidon. “Because we use so much free energy, and more every year, we’ll deplete the reservoir of energy.” He says this would probably show up first in wind farms themselves, where the gains expected from massive facilities just won’t pan out as the energy of the Earth system is depleted.

Using a model of global circulation, Kleidon found that the amount of energy which we can expect to harness from the wind is reduced by a factor of 100 if you take into account the depletion of free energy by wind farms. It remains theoretically possible to extract up to 70 TW globally, but doing so would have serious consequences.

Although the winds will not die, sucking that much energy out of the atmosphere in Kleidon’s model changed precipitation, turbulence and the amount of solar radiation reaching the Earth’s surface. The magnitude of the changes was comparable to the changes to the climate caused by doubling atmospheric concentrations of carbon dioxide [550 ppm].

Where to begin? First, as Schmidt wrote me:

However we extract energy from the ‘active’ system (i.e. not fossil energy), it will affect energy flows in the active system. The more we take, the larger the effect.

Regardless of the size of the impact, it is always renewable. The NS headline is wrong.

We are nowhere near the point at which energy extraction from the active system is a significant player in climate change. It might become so in the far future, but any forseeable growth is well below

In short, the “not renewable claim” is just wrong. It’s a sexed up but dead wrong headline to grab eyeballs.

Heck, our sun will die in about 5 billion years, so I guess solar energy isn’t renewable either.

Second, if by some staggering political conversion and then WWII-scale effort we actually adopted the strategy I have proposed for stabilizing at or below 450 ppm, a strategy that is quite similar to the one proposed by the International Energy Agency, we’d be using “only” 4 TW of wind by 2050.

Third, the Miller, Gans, and Kleidon (MGK10) wind paper has been widely criticized by other leading experts. Here is the summary of the 7-page critique by Stanford’s Jacobson with Cristina L. Archer of Cal State:

We believe the wind power resources from MGK10, estimated as 17″38 TW over land, are low by a factor of up to four due to the unphysical nature of MGK10’s calculations and the fact that such calculations are not comparable with data”derived wind resources. Further, even if MGK10’s wind resources were correct and their scenario realistic, the climate consequences stated by the authors are overestimated by a factor of at least 50″100. In addition, when their scenario is put in a realistic context whereby wind energy replaces thermal power plants, the effects of wind turbines can only be no net change or a reduction in internal energy added to the atmosphere and a significant reduction in other forcings due to the elimination of greenhouse gases (GHGs) and black carbon (BC) from such power plants.

Energetically relevant wake-produced turbulence (not flow-variability) is an assertion and not yet proved by real-world measurements, which indicate rather the opposite. Therefore, energy-replenishment at turbine level is still an unsolved issue. Atmospheric-dynamics processes of energy-replenishment and of resource reduction are still widely unconsidered, but seem to be most relevant. Basic atmospheric dynamics is not correctly applied in the article, so that the model results are questionable.

But you’d never know of these critiques by reading NS. They not only misreported the study and ignored the severe critics, but instead write, “Radical as his thesis sounds, it is being taken seriously.” And then they quote two people who endorses Kleidon’s approach.

Finally, in a box titled, “Is solar electricity the answer?” New Scientist writes “A solar energy industry large enough to make a real impact will require cheap and efficient solar cells.” Apparently the authors have never heard about concentrated solar thermal electricity. Worse, the box ends with this whopper:

Even if solar cells like this are eventually built and put to work, they will still contribute to global warming. That is because they convert only a small fraction of the light that hits them, and absorb most of the rest, converting it to heat that spills into the environment. Sustainable solar energy may therefore require cells that reflect the light they cannot use.

No, no, 100,ooo times no.

We went through this with the authors of the error-riddled book Superfreakonomics and the very confused ‘genius’ who has so impressed Bill Gates, Nathan Myrhvold. The Superfreaks quoted Myrhvold:

“The problem with solar cells is that they’re black, because they are designed to absorb light from the sun. But only about 12% gets turned into electricity, and the rest is reradiated as heat “” which contributed to global warming.”

At one obvious level, New Scientist and Myrhvold wrong because the issue is not how much sunlight PV panels absorb but how much they absorb compared to the material that the panel covered up. Lots of solar panels sit on black roofs.

I realize that because solar and wind power are growing by leaps and bounds that the media feels obliged to play the contrarian, but this piece is ridiculous.

This New Scientist article rivals Charlie Sheen for being incoherent and incorrect.

UPDATE: Stanford’s Mark Jacobson emails me this comment:

This study provides inaccurate and misleading information about wind energy and its physical interactions with the atmosphere for the following reasons.

First, it states that the amount of power in the wind available for wind energy is 18-68 TW and that the climate effects of extracting all such power is equivalent to doubling carbon dioxide. However, wind power results in no net additional heat to the air since it replaces thermal power plants (coal, nuclear, natural gas), all of which directly add the same or more heat to the air than wind power directly through combustion or radioactive decay. These other sources also add carbon dioxide, which wind energy does not do during its operation. Even nuclear adds carbon dioxide continuously through uranium mining, transport, and refinement and, in its lifecycle, puts out 9-25 more carbon dioxide than wind.

Second, even if wind turbines did not replace thermal power plants, the actual heat resulting from converting 18-68 TW of wind power to electricity, which then gets converted to heat is 0.035″0.13 W/m^2. The radiative heating due to doubling of CO2 is 3.7 W/m2, a factor of 28-106 higher. As such, even if 18-68 TW of the wind’s power were extracted, it would affect temperatures by 28-106 times less than doubling carbon dioxide, not the same amount. However, as stated, wind displaces thermal power plants, so its net heat added to the atmosphere is zero.

Third, the world end-use power demand today is 12.5 TW. By 2030, this is expected to grow to 17.9 TW. Converting the world to clean energy and electricity reduces the world power demand in 2030 by 30% to 11.5 TW due to the efficiency of electricity versus thermal combustion. At most, half of this would be powered by wind, resulting in 5.5 TW required, not 18-68 TW. Thus, even if wind power added heat to the air, powering 50% of the world with wind would results in only 1/346th the heating due to doubling carbon dioxide. Again, though, wind adds no heat since it displaces thermal power plants, which directly heat the air the same or more than wind while increasing carbon dioxide and other pollutants.

Fourth, a portion of the heat generated by wind energy is converted back to potential and kinetic energy, so not all of it goes to heat. This was not accounted for by the authors.

Finally, the authors’ wind resource analysis is not based on physical principles or realistic calculations. It is based on simplistic calculations that are extrapolated over the world and unverified against observations. They significantly underestimate the resources.

38 Responses to Yes, wind and wave power are renewable; New Scientist pulls a Charlie Sheen

I gave New Scientist the flick years ago when it got too expensive and the market fundamentalist editorial line became too grating. It was in the hey day of Matt Ridley, the cornutopian free market fantasist (such an inviting path for the scion of a fabulously wealthy elite family to follow)and failed bankster. Crashing Northern Rock Bank, setting off the first bank run in the UK since 1878 and hitting the exchequer for a lazy 27 billion, might deter some, but not a fanatic ideologue like Ridley. He uses his quaintly amusing blog the laughably entitled ‘Rational’ Optimist to peddle climate change denialism, and free market hocus-pocus, apparently having learned nothing from experience, which even laboratory rats in a maze can manage. New Scientist is, after all, a magazine produced by a capitalist corporation, whose owners no doubt own fossil fuel interests, or are related to others that do so. That their ideology MUST eventually infect all their organs is undeniable, and that the process must, over time become more marked and insistent, is obvious. New Scientist has gone the way of all market flesh.

The 47 TW figure appears to be in error. The total (commercial and non commercial) energy use in 2000 was 433 EJ (10e18 J). Divide by the number of seconds in a year (recall that 1 Watt = 1 J/s) and you get about 14 TW, which is the order of magnitude I remember. I’m sure it’s increased since 2000, but not by a factor of 3!

The original Kleidon paper references James Lovelock extensively, so any conclusions regarding wind power are not surprising. I read Lovelock’s fairly recent book on Gaia. He’s a heavy proponent of nuclear power and strongly anti-wind. He believes wind power won’t work in part because climate change will shift atmospheric wind patterns such that windy areas will become less windy. He harps rather heavily on its effect on the U.K. landscape. This qualm is a bit strange considering in the same book he claims that global warming will reduce humanity to a few breeding pairs at the poles by the end of the century (and he’s worried about his view?), something I think he’s backed off on since. Lovelock’s views on climate change are extremely dire – well outside mainstream climate science and heavily disputed. But since views based on his result in some anti-wind power conclusions, expect global warming deniers to promote them.

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships.
At the end of June 2010 the windpower worldwide was 175,000 MW.Energy production was 340 TWh, which is about 2% of worldwide electricity usage; and has doubled in the past three years. Several countries have achieved relatively high levels of wind power penetration, such as 20% of stationary electricity production in Denmark, 14% in Ireland and Portugal, 11% in Spain, and 8% in Germany in 2009. As of May 2009, 80 countries around the world are using wind power on a commercial basis.
According to Global Wind Energy Council,Wind energy must be key climate change solution
“While the power sector is far from being the only culprit when it comes to climate change, it is the largest single source of emissions, accounting for about 40% of CO2 emissions, and about 25% of overall emissions. The options for making major emissions reductions in the power sector between now and 2020 are basically three: energy efficiency and conservation; fuel switching from coal to gas; and renewable energy, primarily wind power.
Wind power does not emit any climate change inducing carbon dioxide nor other air pollutants which are polluting the major cities of the world and costing billions in additional health costs and infrastructure damage. Within three to six months of operation, a wind turbine has offset all emissions caused by its construction, to run virtually carbon free for the remainder of its 20 year life. Further, in an increasingly carbon-constrained world, wind power is risk-free insurance against the long term downside of carbon intense investments.
Given the crucial timeframe up to 2020 during which global emission must start to decline, the speed of deployment of wind farms is of key importance in combating climate change. Building a conventional power plant can take 10 or 12 years or more, and until it is completed, no power is being generated. Wind power deployment is measured in months, and a half completed wind farm is just a smaller power plant, starting to generate power and income as soon as the first turbines are connected to the grid.
The global wind industry has set itself a target of saving 1.5 billion tons of CO2 per year by 2020, which would amount to a total of 10 billion tons saved in this period”.( Global Wind 2008 Outlook for GWEC’s scenarios of wind energy development up to 2050).
There is a spacing between wind turbines in a wind farm that is stipulated mainly to ensure that the wind turbines perform optimally as well as to see that free air is not disturbed after leaving the wind turbine.
While Wind Turbines and other Renewables like Solar help to control climate change, there is no point in criticizing wind energy as a component for climate change.
Dr.A.Jagadeesh Nellore (AP), India
Wind Energy Expert
E-mail: Anumakonda.jagadeesh@gmail.com

If wind power really had an impact on climate through slowing down the wind, I’d argue this would be a good thing.

First to compensate the speeding up of the wind induced by deforestation (following the same argument with changed friction), secondly to dissipate some of the extra kinetic energy the atmosphere holds due to the increased greenhouse effect (due to burning of fossil fuels, deforestation and more).

It is at least interesting that some effort is being put into figuring out what would happen to the climate system if a non-meaningless amount of energy was being removed from it for purposes of energy consumption.

There are many pieces to the puzzle. Renewability doesn’t seem to be an issue though… perhaps more a matter of just what is the atmospheric net energy availability change when (a) renewables are increased and (b) fossils decreased.

What could an average wind farm foot print be, as a force against normal wind pattern. We should find something to compare it with such a medium hill as one under 500 feet. arguably there are millions of such hills scattered throughout the planet. Yet has there been any evidence of lack of wind in the past, none. Of course let us not even consider the effect of small to extremely tall mountains. As far of any historical records there has never been any GW event caused by impedance of wind.

The report even loses more credibility if you considered that most of this planet was covered with forest. Every hill, mountain up to the tree line, valleys and plains were all covered with trees. One thing that a tree is, it’s very efficient at reducing wind velocity.

With all this global wind impedance by the tree covered mountains and hills. There has not been one piece of evidence of a global event caused by the forests impedance of wind. It could be easily argued that a forest is in order of magnitude at stopping the wind then millions of wind turbines.

Are these idiots totally lacking in the ability to think critically? Wind turbines extract energy from the bottom 100 meters of the atmosphere and will in no case cover more than 1% of the earths surface. And then, of course, comes the wind impedance due to natural objects like trees which cover (or used to cover) a large fraction of the land surface of the planet (as Tom points out in #10). Something in this paper is obviously wrong – who refereed this travesty?

I’m not a scientist, but even my simple mind finds this argument to be better suited to a Beck white board than any serious science magazine. I’ve never read “new science” but if this is sample of their scientific reasoning I won’t waste my time. Even assuming their completely illogical assessments were even partially plausible – they do not take into account any improvement in technology, any new technologies, improvements in smart building, the significant potential in efficiency and retrofitting, passive heating/cooling, cool roofs, cool pavement, population stabilization… In addition to the logic of the other posters.

I thought this was an April Fool’s joke, Onion Piece or something in Nude Scientist (which if it isn’t an oxymoron, should be).

Tim (#11) raises a good point (with humor), and likewise we should worry about the earth’s rotation stopping due to Superman’s flying around it. And speaking of Superman, Joe once mused about how he appears to have virtually limitless energy. Has anyone calculated what Superman’s caloric intake would need to be for the feats performed in any one of his films, and compared that to an average American’s?

Thanks! Fighting junk science is a full time job for an army of science journalists. So much junk, so little time. We know something about climate science and so we find junk in their climate reports. What about twenty or fifty other branches of the science tree? I hope people in other specialties keep track of what’s written in this rag and also keep their refutation keyboards at the ready.

Maybe the following analysis is naive. The wind (kinetic energy) is caused by the difference in atmospheric pressure between anticyclones and depressions (potential energy). These in their turn are caused by atmospheric convection caused by heating from solar energy. All the kinetic energy of the wind is normally ultimately converted into heat energy.

Whatever energy we extract from the kinetic energy of the wind with wind turbines is also ultimately converted into heat. Exactly the same amount of heat. While acknowledging that the LOCATION of the dissipation of the heat energy is altered from where it would have been (to a degree), it seems to me that the whole basis of this paper “Large-scale exploitation of wind energy will inevitably leave an imprint in the atmosphere,” says Kleidon. “Because we use so much free energy, and more every year, we’ll deplete the reservoir of energy.”
is very wrong.

His idea of “depleting the reservoir” almost suggests that he believes the wind will just keep on blowing, if it’s energy is not stopped or extracted, like some sort of perpetual motion machine.

about 17 TW comes from burning fossil fuels. So to replace this, we would need to build enough sustainable energy installations to generate at least 17 TW

I have been nagging everybody on and on about how wrong this is and leads to grossly inflated numbers for the amount of renewables we need. The output of renewables like solar, wind and hydro is electricity. The output of fossil fuels is heat. Electric energy is much more efficient in all kinds of uses (electric cars, heat pumps).

I see this coming up again and again and again because people want to have a simple back-of-the-envelope calculation. Never mind that it gives compleletely the wrong number. “It’s simple so I’ll stick with it anyway”. It is simple and it is wrong.

Joe, could you do a thorough post on how to realistically assess renewable energy needs and how the climate solution is not about just replacing fossils with renewables, but also getting serious about energy conservation. These go hand in hand and can not be separated.

Pardon me, but it’s not like the energy is ‘gone,’ but just moved in what is an, essentially, zero sum game. Where you take the energy from the wind in one place, transmit it to another, and use it. During the entire process you create waste heat, which creates convection currents, which cause wind (like the heating of land does…).

Really, anyone who sails can tell you that… You sail in the afternoon because the land heats up. Hot air rises/becomes less dense. Convection starts as the colder, denser air off the surface of the lake or ocean rushes in to fill its place.

The same process also happens in cities. We call it ‘heat pollution.’ There is quite a bit of literature on the subject, on cities such as San Diego, LA, the rainfall in the Sierra’s, Houston, etc.

But the core fallacious issue remains — you’re not destroying energy, you’re moving it in what should end up being a zero-sum game. As opposed to unlocking buried energy and greenhouse gases that will substantially change the climate.

Myhrvold is a classic example of the dangers of a little bit of knowledge, with hubris thrown in. Others talk about the “embedded energy” of solar collectors, as if the energy needed to produce them compares to 100 coal cars a day.

The albedo and heat radiation that Myhrvold refers to can be calculated, but he didn’t bother. Better to make a clever debating point.

Anything we do on very large scale will likely have significant environmental impacts: fossil fuels, wind energy, biofuels, agriculture, the road system, aviation contrails, electronic devices that use electricity and rare-earth substances, etc. etc.

This leads to a few suggestions: 1) conservation is better than energy replacement, where possible (either through energy efficiency or through changes in consumption patterns). 2) a “basket” approach may be better than a single-energy-source approach. 3) reducing the rate of population growth is important.

Having said that, not all large-scale approaches are equal: 1 TW of coal is going to have more impacts than 1 TW of wind.

Either a CO2 concentration of 580ppm is harmless or its not. Imagine that the paper got it exactly right. Windpower at the level of a brazilian TWs of energy would have the same harmful effects.

Great. The answer still isn’t to do nothing and burn that much carbon.

As for the possibility that all of our energy needs will come from wind power in exactly the same academic configuration that the paper assumes, there’s nothing in that. What a paper like this says is, “Don’t put all of your wind turbines in a configuration that will generate this kind of an effect.” Thanks for the heads up: don’t lump our turbines so that they generate significant macro effects. Got it.

Wading through the editorial and the paper(s), and mulling over Joe’s and others’ insights, I had a child- like Ahah moment regarding the state of the Emperor’s clothes here.

The editor and paper writers played into a very common view about GHGs. It is often written that GHGs “add” heat to the atmosphere. Can we agree that in general GHGs contribute to retention of heat in the atmosphere, but the GHGs do not add significant heat, yes? Generally speaking. Retain, retain, retain; not “add.”

The writers got it partly, in that “adding” of heat to the system depends on conversion of energy. But they forgot that GHGs don’t add heat, GHGs act to store it.
So shifting from fossil-energy-to-heat to solar-wind-energy-to-heat, means a serious cut back on two things, one is less heat generated into the system from combustion, and the other less retention of all heat within the system.

When the wind stops blowing all of its kinetic energy has dissipated into heat i.e. the air is slightly warmed. Since wind farms extract the kinetic energy of the wind there is less energy available and the air becomes less warm. The missing heat is however not missing; it has just been moved to where the wind electricity is used. Kleidon suggests that wind farms “could seriously deplete the energy available in the atmosphere”. This is not true since exactly the same amount of energy is re-emitted elsewhere. However, the relocation of heat influences on the wind patterns, which can be seen in larger urban areas where lots of energy is used (emitted).

Empirical studies of large offshore wind farms show that the wake effect from the slowing of the winds by interference with the free-stream wind by upwind wind turbines will be a maximum of 50% or so power loss. This is the result of the increased roughness effect that the multiple turbines have on slowing down the wind speed by the energy extraction performed by the turbines. We can infer that if the entire surface of the planet were covered with a comparable wind farm, then (assuming there is no change in the general circulation of the atmosphere) we would expect that these turbines would produce 50% of the power that a single turbine would otherwise produce.

The cubed root of .5 is .79, indicating that wind speeds at hub height would be approximately 20% less than they would be without the global wind farm. This effect could be considered the worst case of attenuation of extracted wind power, assuming there is not significant alteration of the general circulation. This case corresponds to the blanketing of the Earth’s surface with over 200 million turbines with .6 km spacing.

Assuming we could erect all the turbines we want at sites with 30% capacity factor, to generate 16 terawatts of power requires approximately 13 million, 4 megawatt wind turbines, which is 6% of 200 million figure of the previous paragraph. With such a low penetration, it seems likely that the average attenuation of the available wind power will be much less than 50%.

The assumption that the general circulation is not altered is of course a questionable one, and would have to be verified with modeling computations.

@ Joan Savage
“But they forgot that GHGs don’t add heat, GHGs act to store it.” That is the most important point, and one that people seem to neglect.

If you follow their logic, anything that creates heat in our homes would be additive to the heat content of the home, and it would not take long to make it uninhabitable. But heat escapes our homes much as it escapes the Earth’s atmosphere, and GHG act just as the insulation does in our homes.

The article was published on April 1st – it’s one of many fine articles New Scientist has published as a spoof. There was one a couple of years ago saying studies have shown masturbation is an effective hay fever reliever.

Whilst the debate about wind power etc. is interesting, the story was a very clever April Fool’s joke.

That study finds a maximum extractable amount of wind in the range of 18–68 TW and states “we show with the general circulation model simulations that some climatic effects at maximum wind power extraction are similar in magnitude to those associated with a doubling of atmospheric CO2.”

How long will it be until “certain blogs” praise this result to the sky — and then resume their mantra that climate models such as the one developing at GISS are nothing but rubbish?

Anne van der Bom (#19) – You make excellent points here and these same points in greater detail in comments #133 and #134 on that epic post titled “What would you like to know about clean energy?” 13 posts below before it is swallowed by the street sweeping Vancouver Olympic ice skating post rapidly ascending below it.

Anne, as you might know I specialize in writing long posts no one reads at the end of such epic threads, and I answered your excellent responses to my questions and didn’t want you to miss that.

As I say there, I feel Anne van der Bom and Alan Sangster (#104 comment below) could have an excellent debate here at CP about how solar (and wind) can scale together with electric cars. Anne has an optimistic vision she describes there as well as I’ve ever seen such a vision for solar described anywhere, and electrical engineer Alan Sangster has written a textbook about energy and he feels they won’t scale as easily as Anne thinks.

Also Gnobuddy at #119 chimes in with some calculations that support Alan, but like a Ninja Anne rebuts both.

This is epic stuff that should not be lost, meaning Alan or Anne could be offered a guest post, or best of all Joe could moderate a debate between these two well-thought-out views.

This is critical stuff because we need to know to what degree renewables can be used to anywhere near the scale we know enjoy (or temporarily think we enjoy) with fossil fuels.

Please visit and keep this thread of discussion alive! Here’s the link:

Thanks Joe for your excellent work. To add to the list of flaws in this study, in addition to the ones pointed out above:

1. On the wind resource estimates: The study’s wind resource estimate is based on a series of very questionable calculations. They take the raw wind production, 45,000 TW, and then whittle away 99.9% of that resource based on very questionable assumptions to get 18-68 TW of available energy. First, they use a very weakly supported and obsolete 1979 estimate to assume 98% of that energy is lost to friction. Even if that number were correct, in a world with a lot more wind turbines a lot more of that energy could be captured before it was lost to friction. Next, they throw away another 50% of the remaining energy due to assumed friction that seems to be redundant with what was thrown away in the previous step. Finally, they throw away 75% of the remainder on the assumption that wind produced over the ocean and over glaciated land cannot be used. Even without offshore wind deployment that assumption would be flawed, as wind energy over the ocean interacts with air masses over land and generates wind there. They even note that that is a flaw in their paper. So even if just one of those exclusions is slightly too high, and several appear to be, the wind resource estimate would be orders of magnitude higher. That would put it in line with many of the other wind resource estimates out there, namely Dr. Jacobsen’s work at Stanford.

2. On wind and the climate: First, it is a very misleading to say that adding a massive amount of wind is “comparable” to doubling CO2, as the only metric on which they found climate change that was comparable to doubling CO2 was for changes in precipitation, not temperature. All of their model runs indicate a 100-fold increase in wind energy production would cause zero change in surface temperatures. A 1000-fold increase wind energy output does cause a small, 1 degree C increase in surface temperature, but that is not a real climate forcing, but rather just a localized movement of energy from the upper atmosphere down to the surface as the turbine catches less dense higher level air and it releases heat as it adiabatically expands. Again, no energy is being produced from that, and the earth’s energy balance is not being changed nor the climate forced; this is just a localized phenomenon downwind of a turbine that should normalize as the atmosphere mixes. More importantly, it only occurs at wind penetrations 1,000 times higher than we have today. Back to precipitation: While their model does show a few mm/day change in precipitation as one gets to wind penetrations several hundred times higher than today, this appears to be a sum of absolute value amounts and thus ignores that these effects are going to be both positive and negative in different places and at different times, meaning they will mostly net each other out. Second, most climate models are very bad at predicting changes in precipitation, and in fact, the two models they used disagree strongly on the impact. So the precipitation impact isn’t anything credible anyway.

To sum up these flaws, which are in addition to the ones pointed out by others:

On the wind resource estimate:
– It is a very conservative estimate.
– If more realistic assumptions had been used in several places, the estimated wind resource would have been dozens of times higher, which would put it in line with other estimates produced by researchers at Stanford University and at the U.S. Department of Energy, which calculated that there is enough wind energy to meet humanity’s energy needs dozens or even hundreds of times over.
– Even if the very conservative assumptions are correct, there would be more than enough wind energy to entirely displace humanity’s current use of fossil fuels.
– Wind energy is renewable, and always will be for as long as the sun continues to shine.

On the wind-climate issue:
– The study found humanity’s use of wind energy could increase hundreds of times over without having any impact at all on temperatures.
– Even at unrealistically high wind penetrations 1,000 times greater than we have today, which would produce dozens of times more energy than is used by humans today in total, the only impact on temperature would be to move some energy around in the atmosphere so that temperatures at the earth’s surface appeared slightly higher than they are today, but that impact would dissipate immediately as the earth’s atmosphere mixes.
– The study found that increasing our use of wind energy a hundred or more times over would also have no impact on precipitation or other aspects of the climate. Only at extremely high penetrations approaching 1000 times more wind energy than we have today were the authors able to estimate that there would be small, localized, and likely temporary changes in precipitation, and even then their models were uncertain about that conclusion.

Well, I would like to dissent on your interpretation. Renewable energies do have an impact. If you have enough of them you will impact the climate for sure. I did myself some calculation, Eric Chaisson did other and there is probably a half dozen scientist who came with the same conclusion. This no means that we could not move to all renewable energies. This issue is you there a limit how much energy you can extract or put in the biosphere. If the whole Earth population is going to have the same energy footprint than Americans, this will certainly happen.

Meanwhile, the Wall Street Journal is running true to form. Douglas J. Keenan, writing yesterday in “Opinion Europe,” claims to debunk global warming by showing that, due to an invalid statistical assumption, the NASA temperature record he reproduces in a plot (his Fig. 1) is not statistically significant.

After stating that “I believe that what is arguably the most important reason to doubt global warming can be explained in terms that most people can understand,” Keenan presents a needlessly convoluted argument which most people will not understand. It boils down to his allegation that the IPCC made a bogus assumption about the data and did not report doing the crucial checks of statistical validity that would have revealed their mistake.

It looks like Tamino will take a crack at this. I thought you might enjoy taking your own shot. You can find it here: